1. Field of the Invention
The present invention relates to a display apparatus using a raster-scanning type cathode-ray tube, and more specifically, to a timing signal generating circuit for the display apparatus.
2. Description of the Prior Art
In the prior art display apparatus using a raster scanning type CRT and including a screen memory for storing data for characters and graphic patterns to be displayed on the CRT, a CRT control circuit which supplies synchronizing signals to the CRT and provides the screen memory with the address for the display position on the CRT screen, and a processing circuit (CPU) for reading and writing the screen memory, a timing signal generating circuit for generating timing signals for controlling the operations of the various component circuits is formed by a logic circuit including a combination of gates. As a result, for varying the timings, it is necessary to vary the combinations of gates.